An endoscope is a medical device comprising an optical system within an elongated insertion member. Endoscopy refers to procedures wherein an endoscope is used to visualize and/or treat the interior of the body by passing the distal end of the endoscope through an opening or passage. Endoscopes are provided in various configurations suitable for specific procedures. For example, a laparoscope is an endoscope used to visualize and/or treat the interior of the body by passing the distal end of the endo scope through a small incision such as to allow a health care provider to look directly at the outside of abdominal and pelvic organs, including the fallopian tubes, ovaries, uterus, small bowel, large bowel, appendix, liver, and gallbladder. Similiarly, a ureteroscope is an endoscope that may be passed through the ureter to inspect or treat anatomical structure proximate the ureter.
FIG. 1 illustrates an endoscope system 1 known in the art comprising an endoscope 2, a light/signal cable 12, a light source 3, a video processor 4, and a monitor 5. The light source 3 provides illumination through the endoscope 2 to a target so that the endoscope 2 can generate an image signal which is communicated to the video processor 4 for viewing on the monitor 5.
The endoscope 2 comprises an insertion member 10 and a grip 11. The insertion member 10 comprises an elongated tube 8 comprising a proximal portion 15 terminating at a proximal end 16 and a distal portion 17 opposite the proximal portion 15, terminating at a distal end 18. The insertion member 10 can be made flexible or rigid depending on the type of endoscope 2.
FIG. 2 is a side cross-sectional view of the distal end portion 17 of the endoscope 2 that houses an imaging system 6, in accordance with the embodiment of FIG. 1. The imaging system 6 comprises an imaging sensor 24, an electronic substrate 25 and a signal cable 28. The imaging sensor 24 converts the optical image to an image signal which is communicated along the signal cable 28 to the light/signal cable 12 and to the video processor 4. There are a variety of available imaging sensors 24, such as, but not limited to, charged coupled device (CCD) and complementary metal-oxide semiconductor (CMOS) imaging sensors 24.
The grip 11 is coupled to the proximal end 16 of the insertion member 10 and is used to manipulate the insertion member 10 within the body. The light/signal cable 12 couples with and extends from the grip 11 and provides a flexible connection to the light source 3 and the video processor 4. A connector 14 fixed to the end of the light/signal cable 12 is adapted to removably couple with the light source 3 and the video processor 4. Illumination from a lamp (not shown) in the light source 3 is propagated over the light/signal cable 12 and through a light guide 9 within and extending through the endoscope 2 to the distal end 18 to a target to be observed. In some endoscopes 2, illumination is provided by a light source located at the distal end 18. Suitable light sources 3 include, but are not limited to, a solid-state light source comprising light emitting diodes (LED).
The video processor 4 converts the image signal to a video signal that is communicated to a connected monitor 5. Consequently, an endoscopic image is displayed on the monitor 5 and/or collected by a data recorder (not shown).
The distal end portion 17 of the endoscope 2 houses an objective head 30. The objective head 30 comprises optical components that project and focus an image onto the image sensor 24. The objective head 30 comprises an optical window 21, one or more optical elements 22 in a fixed lens cell 26, and a prism 23 to turn the image path 90 degrees as a mirror. The prism 23 is positioned adjacent to the imaging sensor 24.
The fixed lens cell 26 is adhered to the tube lumen 13 and/or cemented directly to the prism 23 using a permanent adhesive 29. An adhesive resistive to high temperature is used to enable high-pressure steam sterilization of the endoscope 2. However, the fixed lens cell 26 cannot be removed from the distal end portion 17 in order to replace the optical elements 22 without risking significant damage to the distal end portion 17, the objective head 30, and/or the imaging system 6. The use of high temperature to crack the adhesive bond can be damaging to the endoscope 2. Mechanical force directed at cracking the adhesive bond also has a high risk of significant damage to the endoscope 2.
A conventional endoscope 2 has one objective head 30 that is not removable, and therefore, is limited to providing fixed optical properties. Endoscopic surgery commonly requires both a wide angle image and a magnified image. The wide angle image is used for finding an organ, a disease, and gross visualization, whereas a magnified image is used for treatment. A wide angle image can be electronically magnified, but the image degrades significantly with increased magnification. Therefore, it is common that more than one endoscope is used for a particular procedure, leading to increased medical costs.
The increased use of endoscopic diagnostic and treatment procedures is putting a greater burden on the health care industry to contain cost, especially when multiple endoscopes are required, each employing specific optical components suitable for a specific visualization or treatment technique. Endoscopes are sterilized and reused, but have a finite lifetime requiring eventual disposal of expensive, high precision components.
Attempts have been made to remove the optical elements from the insertion member, but not without having to disassemble major components of the endoscope, risking damaging the components, and enduring time-consuming processes. Of particular concern is the breaking of the cement bond between the prism and the lens cell in order to remove the optical elements. This results not only in the issues already mentioned regarding disassembly, but requires a time-consuming process to reassemble and align the lens cell and prism.
Accordingly, there is a need to provide endoscopes having objective heads that provide for relatively easy lens cell removal and reassembly without the negative consequences described. These features will allow for maintenance and refurbishment of endoscopes reducing the costs associated with their use.